What is the strongest known material in the universe?

The strongest known material in the universe is graphene, a form of carbon. Graphene is a single-atom-thick sheet of carbon atoms arranged in a honeycomb lattice. It is the strongest material ever tested, with a tensile strength of 130 gigapascals (GPa). It is also the lightest material known, with a density of just 0.77 mg/cm3.